/Engine/Source/Developer/MaterialBaking/Public/MaterialBakingHelpers.h
Applies a box blur to magenta pixels found in given texture represented by InOutPixels using non-background pixels, this creates a smear across the magenta/filled pixels.
static void PerformUVBorderSmear ( [TArray](API\Runtime\Core\Containers\TArray)< [FColor](API\Runtime\Core\Math\FColor) > & InOutPixels, int32 ImageWidth, int32 ImageHeight, int32 MaxIterations, [FColor](API\Runtime\Core\Math\FColor) BackgroundColor )